Reinstatement value?

Benjamin4

I own a leasehold flat in London SE14, and also own a 1/4 share of the freehold. Our buildings insurance is up for renewal and the quote seems excessive.

The sum insured is £582000. It's a Victorian semi, built approx 1880, standard brick construction with timber joists. There's a basement and three storeys divided into four flats (i.e. one per floor). Small communal area of hallway and stairs from ground to first floors. Footprint of the building is c.80m2 I think. No outbuildings. Nothing particularly special or different about the place, it's just like thousands of other buildings in the area!

When I bought the flat last year the reinstatement value on the home buyer's report was £87000 - which I guess only refers to our flat.

Does £582000 for the whole building sound right? It seems a lot!!